Difference between unit testing and integration testing

Unit testing is performed by developer. Unit testing means developer test the piece of code. Unit testing may be done using unit testing tools.

Integration testing mainly performed by software tester. Integration testing means developer integrate the all the modules. Hence tester has to test the whole system is working correctly after integration with different module also tester has to test that functional flow is not affected after co-relation with other modules. It’s part of black box and gray box testing. When system is integrated with back end and tester has to check database relations with system, it will be called gray box testing.